Due to material discontinuity and inherited forming mechanism, the conductor-connector system of a crimped-type splice connector is highly sensitive to aging of system components, especially during high-temperature operations. Furthermore, due to the increase in power demand and limited investment in new infrastructure, existing overhead power transmission lines often need to operate at temperatures higher than the original designed values. This has led to the accelerated aging and degradation of conductor-connector systems. The implications of connector aging are two-fold: (1) significant increase in electric resistivity of the splice connector and (2) significant reduction in the connector clamping strength. Therefore, splice connectors are one of the weakest links in the electric power transmission infrastructure. The integrity of crimped-type splice connectors is one major concern in the efficiency and reliability of power transmission system. In this paper we present results from high temperature integrity studies of two-stage splice connector systems used for both ACSR and ACSS transmission conductors. The forming process and thermal cycling degradation behaviour are simulated using finite element modeling, which shows good agreement with degradation trends obtained from experimental data. A numerical simulation protocol has been developed to provide guidance in predicting the effective lifetime of ACSR and ACSS splice connector systems.